U.S. patent application number 11/659570 was filed with the patent office on 2008-06-19 for electrical load control device.
This patent application is currently assigned to TOYOTA JIDOSHA KABUSHIKI KAISHA. Invention is credited to Takeshi Hoshiba.
Application Number | 20080143183 11/659570 |
Document ID | / |
Family ID | 36777330 |
Filed Date | 2008-06-19 |
United States Patent
Application |
20080143183 |
Kind Code |
A1 |
Hoshiba; Takeshi |
June 19, 2008 |
Electrical Load Control Device
Abstract
An ECU performs a program including a step of notifying a system
main relay shut-off signal to a high-voltage system using equipment
when a system main relay shut-off demand due to a HV system failure
is generated, a step of shutting off the system main relay when a
high voltage shut-off acknowledging signal from the high-voltage
system using equipment is not unreceived, a step of shutting off
the system main relay when a high voltage shut-off acknowledging
signal from the high-voltage system using equipment is unreceived
and a current value in a high voltage circuit is more than the
predetermined threshold, and a step of shutting off the system main
relay when the current value in the high voltage circuit is not
more than the predetermined threshold and the predetermined period
of time has elapsed from the occurrence of a HV system
malfunction.
Inventors: |
Hoshiba; Takeshi;
(Aichi-ken, JP) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
P.O. BOX 320850
ALEXANDRIA
VA
22320-4850
US
|
Assignee: |
TOYOTA JIDOSHA KABUSHIKI
KAISHA
Toyota-shi
JP
|
Family ID: |
36777330 |
Appl. No.: |
11/659570 |
Filed: |
January 31, 2006 |
PCT Filed: |
January 31, 2006 |
PCT NO: |
PCT/JP2006/301944 |
371 Date: |
February 7, 2007 |
Current U.S.
Class: |
307/31 ;
307/11 |
Current CPC
Class: |
B60L 58/20 20190201;
B60L 58/18 20190201; B60L 50/51 20190201; B60L 2250/10 20130101;
B60L 3/0046 20130101; B60L 3/003 20130101; B60L 3/0061 20130101;
B60L 3/04 20130101; Y02T 10/70 20130101 |
Class at
Publication: |
307/31 ;
307/11 |
International
Class: |
H02J 1/00 20060101
H02J001/00; H02J 3/00 20060101 H02J003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 4, 2005 |
JP |
2005-028534 |
Claims
1. An electrical load control device for controlling a plurality of
electrical loads, to which a power is supplied from an energy
storage mechanism mounted on a vehicle, the electrical load control
device comprising: a detection unit that detects a power shut-off
demand to said first electrical load; a transmission unit that
transmits a power shut-off warning signal to said second electrical
load; a reception unit that receives, from said second electrical
load, information indicating that said second electrical load is in
a power shut-off permitting state in response to the transmission
of said warning signal; and a control unit that controls a relay to
bring said energy storage mechanism and said electrical loads into
one of a connection state and a shut-off state based on the
reception of said information.
2. The electrical load control device according to claim 1, wherein
said control unit brings said relay from a connection state into a
shut-off state, upon receiving said information from said second
electrical load.
3. The electrical load control device according to claim 1, further
comprising a current detection unit that detects a current value of
the power supplied from said energy storage mechanism to said
electrical loads, wherein even in a case where said information is
not received from said second electrical load, when said current
value is not less than a predetermined value, said control unit
brings said relay from a connection state into a shut-off
state.
4. The electrical load control device according to claim 1, wherein
said detection unit detects said power shut-off demand based on
occurrence of a malfunction in said first electrical load.
5. The electrical load control device according to claim 4, wherein
even in a case where said information is not received from said
second electrical load, when a predetermined period of time has
elapsed from the occurrence of said malfunction, said control unit
brings said relay from a connection state into a shut-off
state.
6. The electrical load control device according to claim 1, wherein
said energy storage mechanism is a secondary battery.
7. The electrical load control device according to claim 1, wherein
said first electrical load is an electrical load of a running
system.
8. The electrical load control device according to claim 1, wherein
said second electrical load is an electrical load of an auxiliary
system.
9. An electrical load control device for controlling a plurality of
electrical loads, to which a power is supplied from en energy
storage mechanism mounted on a vehicle, the electrical load control
device comprising: detection means for detecting a power shut-off
demand to said first electrical load; transmission means for
transmitting a power shut-off warning signal to said second
electrical load; reception means for receiving, from said second
electrical load, information indicating that said second electrical
load is in a power shut-off permitting state in response to the
transmission of said warning signal; and control means for
controlling a relay to bring said energy storage mechanism and the
electrical loads into one of a connection state and a shut-off
state based on the reception of said information.
10. The electrical load control device according to claim 9,
wherein said control means includes means for bringing said relay
from a connection state into a shut-off state, upon receiving said
information from said second electrical load.
11. The electrical load control device according to claim 9,
further comprising means for detecting a current value of the power
supplied from said energy storage mechanism to said electrical
loads, wherein said control means includes means for bringing said
relay from a connection state into a shut-off state, when said
current value is not less than a predetermined value, even in a
case where said information from said second electrical load is not
received.
12. The electrical load control device according to claim 9,
wherein said detection means includes means for detecting said
power shut-off demand based on occurrence of a malfunction in said
first electrical load.
13. The electrical load control device according to claim 12,
wherein said control means includes means for bringing said relay
from a connection state into a shut-off state, when a predetermined
period of time has elapsed from the occurrence of said malfunction,
even in a case where said information from said second electrical
load is not received.
14. The electrical load control device according to claim 9,
wherein said energy storage mechanism is a secondary battery.
15. The electrical load control device according to claim 9,
wherein said first electrical load is an electrical load of a
running system.
16. The electrical load control device according to claim 9,
wherein said second electrical load is an electrical load of an
auxiliary system.
Description
TECHNICAL FIELD
[0001] The present invention relates to an electrical load control
device supplying a power from an energy storage mechanism to a
plurality of electrical loads, and particularly to a control device
in the case where the power supplied to the loads is shut off.
BACKGROUND ART
[0002] There has been developed and has come into practical use a
vehicle on which a powertrain, which is called a hybrid system
wherein an engine (for example, a well known engine such as a
gasoline engine or a diesel engine is considered to be used) and an
electric motor are combined, is mounded. Such a vehicle is
controlled so as to achieve the most efficient performance by
automatically switching between operation by the engine and
operation by the electric motor regardless of an accelerator
operation amount by a driver. For example, in the case where the
engine is operated in a steady state and operated for rotating a
generator that charges a secondary battery (battery) acting as an
energy storage mechanism, in the case where the engine is
intermittently operated while the vehicle is running according to
an amount of charge, or the like, the operation and stop of the
engine are repeated regardless of the accelerator operation amount.
In other words, the engine and the electric motor are separately
operated or cooperatively operated, thereby enabling the
improvement in fuel consumption and the great suppression of
exhaust gas.
[0003] As this secondary battery, a high-voltage nickel hydride
battery or the like is used for supplying power to the electric
motor. Additionally, such a vehicle mounted with the hybrid system
is provided with a DC/DC converter for charging an auxiliary
battery or an EPS (Electric Power Steering) that receives a supply
of the power from this secondary battery, instead of receiving a
supply of the power from a conventional auxiliary battery. In other
words, such a vehicle is mounted with a plurality of high voltage
electrical equipment, to which the power from the high voltage
secondary battery is supplied.
[0004] Japanese Patent Laying-Open No. 2004-72892 discloses an
electrical load driving device capable of operating a part of a
plurality of electrical loads even when a different part of the
plurality of electrical loads is out of control. This electrical
load driving device includes a power source that outputs a DC
voltage, a voltage converter that changes a voltage level of the DC
voltage to output an output voltage, a first electrical load that
is driven by the output voltage outputted from the voltage
converter, a second electrical load connected between the power
source and the voltage converter, and control means for stopping
the voltage converter when a malfunction occurs in the first
electrical load.
[0005] According to this electrical load driving device, the
driving device includes the control means that controls so as to
stop a boost converter (voltage converter) that supplies the DC
voltage to an inverter driving an AC motor and to continue to
supply a DC voltage of the DC power source to an auxiliary system
(second electrical load), for example when the AC motor as the
first electrical load is out of control and a charging amount of
the DC power source reaches full charging amount. Accordingly, even
if the main electrical load is out of control, the other electrical
load can be operated without interruption.
[0006] In Japanese Patent Laying-Open No. 2004-72892 described
above, however, the boost converter is stopped and the supply of
the power to the auxiliary system is maintained while continuing on
an ON state of a system main relay, assuming the case where the
control of stopping the boost converter can not be performed, it is
necessary to protect the system by shutting off the system main
relay. Thus, the shutting off the system main relay causes the stop
of the power supply to the electrical load. At this time, when the
power supply to the electrical load is stopped, the actuation of
the electrical load (for example, EPS) is abruptly stopped. In such
a case, a driver feels uncomfortable.
DISCLOSURE OF THE INVENTION
[0007] The present invention has been conceived to solve the
above-described problem, and an object of the invention is to
provide an electrical load control device that supplies power to a
plurality of electrical loads without causing a problem at a time
of shutting off the power supply to the electrical loads.
[0008] The electrical load control device according to this
invention is for controlling a plurality of electrical loads, to
which a power is supplied from an energy storage mechanism mounted
on a vehicle. This control device includes a detection unit that
detects a power shut-off demand to a first electrical load, a
transmission unit that transmits a power shut-off warning signal to
a second electrical load, a reception unit for receiving, from the
second electrical load, information indicating that the second
electrical load is in a power shut-off permitting state in response
to the warning signal, and a control unit that controls a relay to
bring the energy storage mechanism and the electrical loads into
one of a connection state and a shut-off state based on the
reception of the information.
[0009] According to this invention, a power is supplied from a
secondary battery, for example, such as a nickel hydride battery,
one example of the energy storage mechanism mounted on a hybrid
vehicle running with an engine and an electric motor, to a traction
motor (more specifically, from the secondary battery to the
traction motor via a boost converter and an inverter in many
cases). When a malfunction occurs in the first electrical load of a
running system constituted by the traction motor, the boost
converter and the inverter, the power supply from the secondary
battery has to be shut off in order to avoid unstable behavior of
the traction motor. In the case where there exists the second
electrical load that receives the power supply from this secondary
battery, however, when the power supply is shut off promptly in
response to the shut-off demand based on the malfunction of the
first electrical load or the like, a device such as an EPS
activated by the second electrical load abruptly stops normal
actuation. In this manner, a measure is taken against the shut-off
of the power supply from the second battery, by transmitting the
power shut-off warning signal to the second electrical load so that
the EPS or the like changes the power supply source to a backup
power source or an amount of electric-motor assist is gradually
decreased before the power to the second electrical load is shut
off. Then, the second electrical load transmits, to the control
device, the information indicating that the second electrical load
is in the power shut-off permitting state. Upon receiving this
information, the control unit controls the relay so as to bring the
energy storage mechanism and the electrical loads including the
second electrical load into the shut-off state. Thereby, a problem
in the second electrical load caused by prompt shut-off of the
power supply can be suppressed. As a result, it is possible to
provide the electrical load control device that supplies the power
to the plurality of electrical loads without causing a problem at
the time of shutting off the power supply to the electrical
loads.
[0010] Upon receiving the information from the second electrical
load, the control unit preferably brings the relay from the
connection state into the shut-off state.
[0011] According to this invention, a process is taken such that
the problem does not occur even if the power supply to the second
electrical load is shut off, and then the information indicating
that the second electrical load is in the power shut-off permitting
state is transmitted to the electrical load control device. After
this, the control unit controls the relay so as to bring the energy
storage mechanism and the electrical loads into the shut-off state,
and therefore the problem caused by the prompt shut-off of the
power supply to the electrical loads is suppressed.
[0012] More preferably, the electrical load control device further
includes a current detection unit that detects a current value of
the power supplied from the energy storage mechanism to the
electrical loads. Even in the case where the information from the
second electrical load is not received, if a current value is not
less than a predetermined value, the control unit brings the relay
from the connection state into the shut-off state.
[0013] According to this invention, it is assumed the case where
the information indicating that the second electrical load is in
the power shut-off permitting state can not be received, after the
process is taken such that the problem does not occur even if the
power supply the second electrical load is shut off to. In such a
case, if the current value of the power supplied from the secondary
battery is not low, unstable behavior of the traction motor may
occur. Therefore, even in the case where the information from the
second electrical load is not received, if the current value is not
less than the predetermined value, the relay is brought into the
shut-off state, thereby the problem in the first electrical load
can be prevented from occurring.
[0014] More preferably, the detection unit detects the power
shut-off demand based on the occurrence of the malfunction in the
first electrical load.
[0015] According to this invention, when the malfunction occurs in
the first electrical load of the running system constituted by the
traction motor, the boost converter and the inverter, the power
shut-off demand can be detected.
[0016] More preferably, even in the case where the information from
the second electrical load is not received, when a predetermined
period of time has elapsed from the occurrence of the malfunction,
the control unit brings the relay from the connection state into
the shut-off state.
[0017] According to this invention, it is assumed the case where
the information indicating that the second electrical load is in
the power shut-off permitting state can not be received, after the
process is taken such that the problem does not occur even if the
power supply to the second electrical load is shut off. In such a
case, the continuous connection state of the relay under the state
that the malfunction occurs in the running system causes a
possibility of further expanding a malfunction in the running
system, inducing a secondary failure, or generating unstable
behavior of the traction motor. For this reason, in order to
prevent the occurrence of such problems, the power supply is shut
off even if the relay is shut off. Therefore, even in the case
where the information from the second electrical load is not
received, when the predetermined period of time has elapsed from
the occurrence of the malfunction, the relay is brought into the
shut-off state, whereby it is possible to prevent the occurrence of
a new problem.
[0018] More preferably, the energy storage mechanism is a secondary
battery.
[0019] The power supply from the secondary battery as the storage
mechanism can be shut off without causing a problem in the
electrical equipment.
[0020] More preferably, the first electrical load is an electrical
load of a running system.
[0021] In the case where a malfunction occurs in the electrical
load of the running system constituted by the traction motor, the
boost converter and the inverter, the power supply can be shut off
without causing a problem in the second electrical equipment.
[0022] More preferably, the second electrical load is an electrical
load of an auxiliary system.
[0023] In the case where a malfunction occurs in the first
electrical load, it is possible to shut off the power supply
without causing a problem in an auxiliary system as the second
electrical equipment such as an EPS, an electric compressor of an
air conditioner, a DC/CD converter charging an auxiliary battery,
or the like.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is a view showing an entire structure of a vehicle
mounted on a control device of a power circuit according to an
embodiment of the present invention.
[0025] FIG. 2 is a flowchart showing a control structure of an
malfunction determining program performed in an ECU of FIG. 1.
BEST MODES FOR CARRYING OUT THE INVENTION
[0026] An embodiment of the present invention will be hereinafter
described with reference to the drawings. In the following
description, the same reference numerals are given to the same
parts and these names and functions are also the same. Accordingly,
the detailed description thereof will not be repeated.
[0027] With reference to FIG. 1, a description will be given of a
vehicle mounted with a control device according to an embodiment of
the present invention. This vehicle includes a battery 100, an
inverter 200, a traction motor 300, a condenser 400, a system main
relay 510 (SMR (1) 500, limiting resistor 502, SMR (2) 504, SMR (3)
506), and an ECU (Electronic Control Unit) 600. The control device
according to the embodiment is realized by a program preformed by
ECU 600. In this embodiment, the description is given of the
vehicle that is an electric vehicle running only by a driving force
from traction motor 300. However, the vehicle mounted with the
electrical load control device according to the present invention
is not limited to the electric vehicle, and the control device can
be mounted on other vehicle such as a hybrid vehicle or a fuel-cell
vehicle.
[0028] Battery 100 is an assembled battery in which a plurality of
modules, each of which includes a plurality of cells connected in
series, are connected in series. A capacitor can be used in place
of battery 100.
[0029] Inverter 200 includes six IGBTs (Insulated Gate Bipolar
Transistor) and six diodes, each of which is connected in parallel
to the each IGBT so as to flow a current from an emitter side to a
collector side of the IGBT. Inverter 200 switches a gate of the
each IGBT on/off (supplies/shuts off an electric current) based on
a control signal from ECU 600, thereby a current supplied from
battery 100 is converted from an AC current to a DC current to
supply the DC current to traction motor 300. A further detailed
description is not repeated here, since well known technique can be
applied to inverter 200 and the IGBT.
[0030] Traction motor 300 is a three-phase motor. A rotating shaft
of traction motor 300 is finally connected to a drive shaft (not
shown) of the vehicle. The vehicle runs with a driving force from
traction motor 300.
[0031] Condenser 400 is connected to inverter 200 in parallel.
Condenser 400 stores a load once so as to smooth a power supplied
from battery 100 or a power supplied from inverter 200. The
smoothed power is supplied to inverter 200 or battery 100.
[0032] System main relay 510 is constituted by SMR (1) 500 and SMR
(2) 504 on a positive electrode side, and SMR (3) 506 on a negative
electrode side. SMR (1) 500 and SMR (2)504 are provided on a
positive electrode side of battery 100. SMR (1) 500 and SMR (2) 504
are connected in parallel. Limiting resistor 502 is connected in
series to SMR (1) 500. SMR (1) 500 is an SMR for precharge that is
connected before SMR (2) 504 is connected so that an inrush current
is prevented from flowing in inverter 200. SMR (2) 504 is an SMR on
a positive side that is connected after SMR (1) 500 is connected
and the precharge is completed. SMR (3) 506 is an SMR on a negative
side that is provided on the negative electrode side of battery
100. Each of the SMRs is controlled by ECU 600.
[0033] ECU 600 performs a program stored in a ROM (Read Only
Memory), based on an ignition switch (not shown), a pressing amount
of an accelerator pedal (not shown), a pressing amount of a brake
pedal (not shown) or the like, and controls inverter 200 and the
each SMR, thereby enabling the vehicle to run in a desired
condition. A voltmeter 602 that detects a voltage of condenser 400
is connected to ECU 600. A voltage V (1) of inverter 200 (traction
motor 300) is detected by detecting the voltage of condenser
400.
[0034] In addition, a voltmeter 604 that detects a voltage V (B) of
battery 100 and an ammeter 606 that detects a current I (B) of
battery 100 are connected to ECU 600.
[0035] SMR (1) 500, SMR (2) 504 and SMR (3) 506 are a relay that
closes a point of contact to brought into an ON state when an
exciting current is supplied to a coil. A description will be given
of the relationship of the operation state of SMR (1) 500, SMR (2)
504 and SMR (3) 506 and the position of the ignition switch. The
ignition switch has OFF position, ACC position, ON position and STA
(start) position. When a power source is shut off, that is to say,
when the ignition switch is positioned in the OFF position, ECU 600
brings all of SMR (1) 500, SMR (2) 504 and SMR (3) 506 into an OFF
state. In other words, ECU 600 brings the exciting current to the
coil of each SMR (1) 500, SMR (2) 504 and SMR (3) 506 into an OFF
state. When an engine key is inserted into a key cylinder and then
is turned, the position of the ignition switch is switched to the
OFF position, the ACC position, the IGON position and the STA
position, in that order, and is automatically returned from the STA
position to the ON position. The ignition switch is not limited to
thus described ignition switch, and the following may be adopted.
When a key in place of the engine key (also referred to as a smart
entry key) is inserted into a key slot (or a driver carries the
smart entry key and sits in a driver's seat) and a push button
switch (also referred to as a power switch) is pushed, the position
of a power source is switched to an OFF position, an ACC position,
an IGON position and an HV system starting position, in that
order.
[0036] In addition, this vehicle is provided with an EPS 700, to
which a power is supplied from battery 100 and which assists
steering operation with the electric motor, and an EPS controller
710 that is a control device of EPS 700. For example, when a rated
voltage of battery 100 is about 200 V, EPS 7000 reduces a voltage
to about 42 V with a built-in DC/DC converter, thereby a power is
supplied to an EPS motor. An electrical load, to which a power is
supplied from battery 100, may be a DC/DC converter that charges a
low voltage battery (auxiliary battery).
[0037] This vehicle also includes a boost converter 800 provided
between battery 100 and inverter 200. Boost converter 800 boosts
the rated voltage of battery 100, for example, from about 200 V to
about 500 V (a rated voltage of a motor). Boost converter 800 is
constituted by two IGBTs or a reactor that reduces current
variation.
[0038] At the time of connecting the power source, that is, when
the position of the ignition switch is switched from the OFF
position to the STA position through the ACC position and the ON
position, ECU 600 firstly brings SMR (3) 506 into an ON state, and
then brings SMR (1) 500 into an ON state to perform precharge.
Since limiting resistor 502 is connected to SMR (1) 500, an
inverter voltage V (I) slowly rises even if SMR (1) 500 is brought
into the ON state, thereby the occurrence of an inrush current can
be prevented. When the position of the ignition switch is switched
from the OFF position to the ON position, a malfunction determining
process described later is performed. It is to be noted that the
malfunction determining process may be performed when the position
of the ignition switch is switched from the OFF position to the ACC
position.
[0039] When inverter voltage V (I) reaches, for example, about 80%
of a battery voltage V (B), ECU 600 completes precharge and then
brings SMR (2) 504 into an ON state. When inverter voltage V (I)
approximately equals the battery voltage V (B), ECU 600 brings SMR
(1) 500 into an OFF state and a current supply from battery 100 is
brought into an ON state.
[0040] In the meantime, when the position of the ignition switch is
switched from the ON position to the OFF position, ECU 600 firstly
brings SMR (2) 504 into an OFF state and subsequently brings SMR
(3) 506 into an OFF state. As a result, electrical connection
between battery 100 and inverter 200 is shut off to be brought into
a power source shut-off state. At this time, a remaining voltage on
a drive circuit is discharged, and inverter voltage V (I) is
gradually converges to about 0 V (voltage at the time of shut-off).
It is to be noted that the voltage at the time of the shut-off is
not necessarily 0 V, and may be a weal voltage, for example, about
2 or 3 V.
[0041] While ECU 600 thus brings system main relay 510 from the ON
state to the OFF state, ECU 600 further performs control peculiar
to the present invention as described below, when bringing system
main relay 510 into the OFF state.
[0042] With reference to FIG. 2, a description will be given of a
control structure of a program performed by ECU 600 serving as the
electrical load control device according to the embodiment. It is
to be noted that a program represented by the following flowchart
is repeatedly performed at predetermined time intervals.
[0043] In Step (hereinafter, abbreviated step as S) 100, ECU 600
determines whether or not a shut-off demand of system main relay
510 due to a HV system failure is generated. At this time, ECU 600
detects that the system main relay shut-off demand due to the HV
system failure is generated, for example when a malfunction occurs
in battery 600 based on information of voltmeter 604 of battery 100
inputted from ammeter 606. ECU 600 may also determine that the
system main relay shut-off demand due to the HV system failure is
generated based on a malfunction detecting signal inputted from
Inverter 200 or boost converter 800. When the system main relay
shut-off demand due to the HV system failure is generated (YES in
S100), the process proceeds to S200. If not (NO in S100), the
process is terminated.
[0044] In S200, ECU 600 notifies a system main relay shut-off
signal to a high-voltage system using equipment. At this time, ECU
600 notifies the system main relay shut-off signal to, for example,
EPS controller 710.
[0045] In S300, ECU 600 determines whether or not a high voltage
shut-off acknowledging signal from the high-voltage system using
equipment is unreceived. When the high voltage shut-off
acknowledging signal from the high-voltage system using equipment
is unreceived (YES in S300), the process proceeds to S400. If not
(NO in S 300), the process proceeds to S700.
[0046] In S400, ECU 600 detects a current value in a high voltage
circuit. At this time, ECU 600 detects the current value in the
high voltage circuit based on a signal inputted from ammeter
606.
[0047] In S500, ECU 600 determines whether or not the current value
in the high voltage circuit is not more than a predetermined
threshold. When the current value in the high voltage circuit is
not more than the predetermined threshold (YES in S500), the
process proceeds to S600. If not (NO in S500), the process proceeds
to S700.
[0048] In S600, ECU 600 determines whether or not a predetermined
period of time has elapsed from the occurrence of the HV system
failure. When the predetermined period of time has elapsed from the
occurrence of the HV system failure (YES in S600), the process
proceeds to S700. If not (NO in S600), the process is returned to
S300, and the processes in S300 to S500 are repeatedly
performed.
[0049] In S700, ECU 600 brings the system main relay 510 into a
shut-off state. The specific method for bringing the system main
relay 510 into the shut-off state is that as previously
described.
[0050] A description will be given of the operation of an
electrical load circuit controlled by ECU 600 serving as the
electrical load control device according to the embodiment and
based on the above-described structure and flowchart.
[0051] When the system main relay 510 is brought into a connection
state, a power is supplied from battery 100 to inverter 200 via
boost converter 800, or a power is supplied from battery to EPS
700. When a malfunction in battery 100 is detected, a malfunction
in boost converter 800 is detected, a malfunction in inverter 200
is detected, or a malfunction in motor 300 is detected, a demand
for shutting off the system main relay 510 is generated (YES in
S100). The system main relay shut-off signal is notified to boost
converter 800, inverter 200, or EPS 700 and the like as the
high-voltage system using equipment (S200).
[0052] EPS controller 710 receiving this system main relay shut-off
signal performs a process for switching a power supply circuit
supplied to EPS 700 from a main power supply circuit to a backup
circuit supplied via a low voltage battery. In addition, ESP
controller 710 controls EPS 700 such that EPS 700 gradually reduces
an assist amount of an electric power steering. After that, EPS
controller 710 transmits the high voltage shut-off acknowledging
signal to ECU 600.
[0053] When all the high voltage shut-off acknowledging signals
from the high-voltage system using equipment are received (NO in
S300), the system main relay 510 is shut off (S700).
[0054] On the other hand, when the high voltage shut-off
acknowledging signal from the high-voltage using equipment is
unreceived (YES in S300) and the current value in the high voltage
circuit is more than the predetermined threshold (NO in S500), the
system main relay 510 is shut off (S700),
[0055] In addition, when the current value in the high voltage
circuit is not more than the predetermined threshold (YES in S500)
and the predetermined period of time has elapsed from the
occurrence of the HV system failure (YES in S600), the system main
relay is shut off (S700).
[0056] As described above, when the system main relay has to be
shut off due to the failure of the HV system, a warning signal of
performing the shut-off of the system main relay is notified in
advance to the equipment using the high voltage system by a program
performed by the ECU as the electrical load control device
according to the embodiment. Even if the high voltage system is
shut off, the high-voltage system using equipment that has received
the notification of the shut-off warning signal of the system main
relay transmits the high voltage shut-off acknowledging signal to
the ECU after performing a process for preventing the occurrence of
the problem caused by the shut-off. In the ECU, when the high
voltage shut-off acknowledging signal from the high voltage system
using equipment is received, the main relay is shut off.
Accordingly, a new problem does not occur, since the high voltage
power is shut off the high-voltage system using equipment. Even in
the case where the current value in the high voltage circuit is not
more than the predetermined threshold and the predetermined period
of time has elapsed from the occurrence of the HV system failure,
the system main relay is shut off. This is because, if the power
from the battery is not actually consumed, for example, unstable
behavior of the traction motor does not occur. Therefore, when
predetermined period of time has elapsed, the system main rely is
shut off. In addition, in the case where the current value in the
high voltage circuit is not more than the predetermined threshold,
since the power from the battery is consumed, there is a
possibility of the occurrence of unstable behavior of the motor.
Therefore, even if the high voltage shut-off acknowledging signal
from the high voltage system using equipment is not received, the
system main relay is shut off.
[0057] The embodiment disclosed herein is to be considered in all
respects as illustrative and not restrictive. The scope of the
invention is indicated by the claims rather than the foregoing
description and all changes that come within the meaning and range
of equivalency of the claims are intended to be embraced
therein.
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